Table 1.
Characteristics of participants (n=479)
| Characteristics | Overall | Boys | Girls |
|---|---|---|---|
| Total | 479 (100) | 256 (53.4) | 223 (46.6) |
| Age (mo) | 71.1±1.6 | 71.1±1.6 | 71.1±1.6 |
| Body mass index (kg/m2) | 15.8±1.7 | 15.8±1.7 | 15.8±1.7 |
| Maternal age (y) | 31.4±3.6 | 31.5±3.6 | 31.2±3.5 |
| Maternal blood cadmium level (μg/L) | 0.7±0.3 | 0.7±0.3 | 0.7±0.3 |
| Maternal blood lead level (μg/dL) | 1.4±0.4 | 1.4±0.5 | 1.3±0.3 |
| Maternal education level | |||
| High school or less | 75 (15.6) | 40 (15.6) | 35 (15.7) |
| University or above | 404 (84.3) | 216 (84.4) | 188 (84.3) |
| Current smoker | 31 (6.4) | 19 (7.4) | 12 (5.4) |
| Secondhand smoke exposure | |||
| No | 87 (18.2) | 44 (17.2) | 43 (19.3) |
| Yes | 392 (81.8) | 212 (82.8) | 180 (80.7) |
| Parity | |||
| First child | 292 (61.0) | 156 (60.9) | 136 (61.0) |
| Second child or above | 187 (39.0) | 100 (39.0) | 87 (39.0) |
| K-ARS scores | |||
| Total | 6.2±5.8 | 6.9±5.7 | 5.4±5.9 |
| Attention deficit | 3.4±3.2 | 3.9±3.1 | 3.0±3.3 |
| Hyperactivity | 2.7±3.1 | 3.0±3.0 | 2.3±3.0 |
Values are presented as mean±standard deviation or number (%).
SD, standard deviation; K-ARS, Korean attention-deficit/hyperactivity disorder rating scale.